generally you have a seam in the perimeter counters because they are long or angled, larger than a single slab, or cannot be transported without breaking because they are large and angled. islands are usually one piece unless they are large.

we have a slide in stove in our island, there is no seam for that, just a notch for the stove. i'd expect since a stove would go most of the way through a perimeter counter (if not all the way...) then a seam would be expected there UNLESS its near the end of the counter, not in the middle.